Barrier walls that are formed from a plurality of elongated, vertically oriented piles typically are driven into the earth to a depth sufficient to support the panels in an upright attitude. In some cases, the piles are in the form of extruded structural panels and are formed with male and female opposed edges so that similar panels can be locked together at their adjacent side edges to form a continuous barrier wall. Because of the strength required of the panels when being driven into the earth and the strength required under load conditions, typically, the panels have been made of steel or aluminum. Frequently, steel and aluminum panels have over-sized cross sections to allow for the effects of corrosion. The additional material used in over-sizing increases the costs of the piles due to the material itself as well as the costs associated with handling the heavier piles.
In recent years, structural panels have been constructed of polyvinyl chloride and other plastics having relatively low tensile strength and high compression strength. The panels are extruded in a continuous manufacturing process, and in order to provide the strengths in the panel necessary to withstand the loads that are expected to be applied to the panels, the thicknesses of the panels have been increased over the typical thickness of similar panels formed of steel or aluminum. Further increases in thickness of the plastic provides a diminishing return. The increased bending strength does not offset the cost of the additional plastic.
In order to produce a structural panel formed of a synthetic material that is to be used as a driven pile in the formation of a barrier wall, the panels have been formed in various strengthening cross-sectional shapes, such as V-shapes, Z-shapes, U-shapes, etc., that provide resistance to bending in response to the application of axial and/or lateral loads to the panels. Further, the panels have been constructed so as to have at their opposite edges male and female locking elements, so that the edge of one panel locks with and supports the edge of an adjacent panel.
After the first panels have been driven into place, subsequent panels can be driven into place adjacent the previously driven panels with their male and female edges locked together as they are driven, thereby forming a continuous barrier wall. The barrier wall typically is held in place with a series of horizontally placed structural members, or wales, that extend along the exposed outer surface of the barrier wall. The wales frequently are held in place with a plurality of tie rods. The tie rods extend through the wale, the barrier wall, and the soil disposed behind the barrier wall, and have one end secured to the wale and another end which is secured to a force abutter. Typically, the force abutter is a reinforced cement wall disposed a desired distance behind the barrier wall such that adequate force is exerted from the force abutter through the tie rods on the barrier wall, thereby maintaining the barrier wall in the desired position. As constructed, these barrier walls have a number of obstructions, such as wales, tie rods, etc., present on the exposed outer surface of the barrier wall. These obstructions are subject to damage from, and may cause damage to, boats, barges, and like craft that frequently operate near and are secured to such barrier walls.
Therefore, there is a need for improved extruded structural members which address these and other shortcomings of the prior art.